231 



Miles and 

 Kilometres. 



in -9 m. Ducks station — Alt. 1,146 ft. (349 m.). At 

 180 • 1 km. this point the Nicola rocks are specially well seen, 

 across the river. Three kilometres to the south- 

 east, the Tertiary lavas are now dipping at 

 angles varying from 45 to 90 , indicating the 

 local vigour of the last orogenic deformation 

 (late Miocene) in British Columbia. 



At and beyond Ducks station, the silt 

 terraces are very conspicuous. 



At the 118th mile-post, nine kilometres 

 beyond Ducks, the Triassic series can be seen 

 north of the river, resting on the Carboniferous 

 (Pennsylvanian) limestone, the light gray 

 colour of the latter contrasting well with the 

 deep tint of the Nicola lavas. The relation 

 is that of unconformity, since the lavas are under- 

 lain by a basal conglomerate containing chert 

 pebbles derived from the limestone. The con- 

 glomerate and the plane of unconformity dip 

 east at an average angle of about 50 , The 

 limestone has a variable attitude but also dips 

 at a high angle to the eastward. The agreement 

 seems to show that the pre-Triassic deforma- 

 tion of the Carboniferous strata was not 

 severe. 



This is one of the best exposed contacts 

 between these two great series yet found in 

 British Columbia. 



Continuing to Kamloops, the route crosses the 

 Carboniferous rocks. (See p. 144). The dark- 

 coloured ledges are chiefly composed of cherty 

 quartzites and altered argillites, but some basic 

 volcanic ash and coarser pyroclastic material is 

 also interbedded. At intervals, light gray 

 vertical bands represent as many occurrences of 

 older fossiliferous Pennsylvanian limestone. 

 The general structure north of the river, through 

 to the North Thompson river, is the mono- 

 clinal. The strike averages N. 35-40 W. ; the 

 dip, 75-80 to the N.E. Yet there are a few 

 local reversals of the always steep dip, and it is 

 likely that the total thickness calculated from 

 35069— 9A 



